In recent years, for a package or a device having an electronic device such as an infrared ray sensor, gyro sensor (angular velocity sensor), temperature sensor, pressure sensor, and acceleration sensor vacuum-encapsulated therein, there has been a demand for miniaturization, technological advances in performance, and cost reductions. In particular, for a package or a device having an infrared ray sensor, which is used in a surveillance camera for night-time security or is used in thermography for calculating and displaying temperature distribution, mounted therein, the inside thereof needs to be vacuum-encapsulated.
In general, as an infrared ray detecting devices, a quantum type and a thermal type exist. Among these, although the thermal type has a lower level of tracking capability compared to that of the quantum type, since it is of a form which detects a relative thermal quantity, it may be made in a non-cooling form and the structure thereof may be simplified. As a result, manufacturing cost can be kept low with the thermal type.
In a package or device having this thermal type infrared ray sensor mounted therein, an infrared ray which has been transmitted through a window is absorbed by a light-receiving section of the detecting device, and the temperature of the vicinity of the light-receiving section changes. Further, resistance change associated with this temperature change is detected as a signal.
Here, in order to detect a signal with a high level of sensitivity, the light-receiving section needs to be thermally insulated. Therefore, this thermal insulation property has been conventionally ensured by having a structure in which the light-receiving section is floated in an empty space, or by arranging the detecting element inside a vacuum container.
As such a thermal type non-cooling infrared ray sensor device, for example, there is a structure disclosed in Japanese Unexamined Patent Application, First Publication No. H11-326037 (refer to Patent Document 1).
FIG. 42 shows a cross-sectional structure of this non-cooling infrared ray sensor device.
This device includes a substrate 101 having a light-receiving section 102, and an infrared transmitting window 104 having one or more through holes 105, which is arranged at a distance from the light-receiving section 102 while a space 103 is present therebetween. Furthermore, the substrate 101 and the transmitting window 104 are air-tightly fixed on a bond surface which completely surrounds the light-receiving section 102. In this package, there is provided a structure in which the space 103 between the substrate 101 and the transmitting window 104 is made a vacuum by evacuating the air therein through the through holes 105, and then the through holes 105 are sealed by a sealing material 106 such as solder.
Moreover, a similar thermal type non-cooling infrared ray sensor device, there is a structure disclosed in Japanese Unexamined Patent Application, First Publication No. H10-132654 (refer to Patent Document 2).
FIG. 43 shows a cross-sectional structure of this non-cooling infrared ray sensor device.
This device includes: a base 112 having an infrared ray detecting element 111; a lid 115 which has an infrared ray incident hole 116, through which an infrared ray is incident, and which is joined with the base 112; an infrared optical component 117 which is fixed on the lid 115 by a fixing material 118 so as to block the infrared ray incident hole 116; a vacuum sealing hole 119 provided so as to pass through the lid 115; and a sealing material 120 which has a melting temperature lower than a melting temperature of the fixing material 118, and which blocks the vacuum sealing hole 119.
Furthermore, in general, there occurs a phenomenon such that once an electronic device has been encapsulated in a vacuum atmosphere, gas molecules (H2O, O2, N2, and so forth) having been adsorbed on the surface inside a vacuum encapsulating package are slowly released into the space inside the package as time advances, and the level of vacuum within the package is reduced. As a result, there is a problem in that the performance of the electronic device is reduced (in an infrared ray sensor for example, the sensitivity of output signals is reduced).
Consequently, in a conventional vacuum encapsulating package, in order to remedy this type of problem, a material called a “getter” is mounted inside the package, so that even in a case where outgassing occurs inside the package described above, this getter absorbs the gas molecules, thereby preventing the level of vacuum from being reduced.
As a material of the getter, for example, zirconium, vanadium, iron, or an alloy of these materials is used. However, if it is left in the atmosphere, gas molecules become adsorbed on the surface thereof, and consequently it becomes saturated and unable to adsorb gas no more. Therefore, before mounting it inside the vacuum encapsulating package and vacuum encapsulating it, it is necessary to perform a so-called “activation” process, in which heat (approximately 400° C. to 900° C.) is applied to the getter to thereby release molecules on the surface, and having completed the activation process, the getter needs to be encapsulated in the vacuum atmosphere.
As such a thermal type non-cooling infrared ray sensor device having a getter mounted therein and a manufacturing method thereof, for example, there is a technique disclosed in Japanese Unexamined Patent Application, First Publication No. 2003-139616 (refer to Patent Document 3). FIG. 44 shows a cross-sectional structure of this non-cooling infrared ray sensor device. In this structure, there is disclosed a technique in which a getter 122 is connected to terminals 113, a connecting point of which is provided each inside and outside the package, and by flowing electric current to these terminals 113 from the terminals 113 outside the package, a heater 110 (which is electrically connected to the terminals 113: refer to FIG. 45) built into the getter 122 is heated and the getter 122 is heated and activated at the same time. Furthermore, in Patent Document 3 mentioned above, as shown as another technique in FIG. 46, there is also disclosed a method in which the getter 122 is weld-bonded on the inner surface of a metal cap 124, and the getter 122 is heated and activated by bringing a heated external heater 125 in contact with the metal cap 124.
Moreover, as a thermal type non-cooling infrared ray sensor device having the getter 122 mounted therein, and a manufacturing method thereof, in addition to these, there is a technique disclosed in Japanese Unexamined Patent Application, First Publication No. H11-326037 (Patent Document 1 mentioned above). That is to say, the method, as shown in FIG. 47, is such that a getter 122 wired through vacuuming through holes 105 provided in an infrared ray transmitting window, is arranged within a space 103 between a substrate 127 and an infrared optical component (detection target selecting material) 117, and the getter 122 is heated and activated by applying electricity to a wire 130 arranged through the through holes 105. Moreover, there is a technique disclosed in Japanese Unexamined Patent Application, First Publication No. 2006-10405 (refer to Patent Document 4). That is to say, the method, as shown in FIG. 48, is such that a getter 122 mounted on a spacer 131 connected to an infrared optical component 117 is brought in contact with a lower heater 135 and is heated and activated within a vacuum chamber 133, and then a substrate 127 on which an infrared ray detecting device 111 is formed, is bonded with the infrared optical component 117 within a vacuum atmosphere.    [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. H11-326037    [Patent Document 2] Japanese Unexamined Patent Application, First Publication No. H10-132654    [Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2003-139616    [Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2006-10405